I wouldn't share the question since I did accept their confidentiality agreement. But let me say, I was asked to solve a problem that in its crude implementation would give O(n^2). The interviewer accepted it to be a fair solution but wanted to know how I could convert that to O(1). I did. Based on a reasonably well known solution that is pretty similar to an LRU Cache that you can look up on the internet. I emphasized *how* the solution is O(1). Now, either you can have a difference of opinion, but to rule that solution out, and provide a negative feedback to the recruiter, without opening your mind up for other possible solutions, my past experiences, my potential to think out of the box (even if you think that was not in your line of thinking and hence not an acceptable solution), shame on you. You are Apple, and you supposedly think out of the box. Terribly disappointed. That round should have easily taken me to campus interview, but didn't happen.